Spark Max error after connecting to Neo 550

We have a new Spark Max that was confirmed to be working after connecting to a power supply and a good motor. It was then connected to a different motor, and upon startup it gave a slow blinking red light (instead of slow blinking magenta like all the other good ones). We reconnected to the previous good motor and it continued to blink red. Connected to the REV Hardware Client and it is not even recognized. We tried the same procedure with another previously identified working Spark Max, and the same thing happened. It went from working (magenta) to not working (red) and not recognized by the hardware client. 2 questions: 1) what is the meaning of a blinking red light? This blink pattern is not identified in REV documentation. 2) Can a motor cause a Spark Max to go bad? The motor is a Neo 550.